CN112165720B

CN112165720B - Adaptive edge node information reporting method for THz-WPAN

Info

Publication number: CN112165720B
Application number: CN202011162060.5A
Authority: CN
Inventors: 李宁; 宋瑞良; 苏新; 郭黎; 任智
Original assignee: CETC 54 Research Institute
Current assignee: CETC 54 Research Institute
Priority date: 2020-10-27
Filing date: 2020-10-27
Publication date: 2022-04-12
Anticipated expiration: 2040-10-27
Also published as: CN112165720A

Abstract

The invention discloses a self-adaptive edge node information reporting method for a THz-WPAN, and belongs to the technical field of THz-WPAN. The invention introduces the concept of edge nodes in the communication of the cross-terahertz wireless personal area network, is beneficial to finding out the reason of the interference problem suffered by the N-CTAP time period, and provides a solution thought for solving the interference. Meanwhile, the invention provides a self-adaptive edge node information reporting method. When the node finds that the node is the edge node, the node can report the node type information to the PNC of the personal area network where the node is located efficiently and timely under the condition that extra control overhead is not increased. Thus, if the PNC finds a DEV to be an edge node, measures can be taken on the slot allocation to reduce or even eliminate inter-PAN interference caused by the edge node.

Description

Adaptive edge node information reporting method for THz-WPAN

Technical Field

The invention relates to the technical field of THz-WPAN, in particular to an adaptive edge node information reporting method for THz-WPAN, which is helpful for reducing or eliminating inter-PAN interference caused by edge nodes.

Background

Terahertz wireless personal area network (THz-WPAN) is a wireless ad hoc network with THz waves as carriers. In the network, each Wireless Personal Area Network (WPAN) is composed of a plurality of DEV nodes, wherein a node with a higher priority competes for becoming a PNC of the network, and the node provides basic networking information through a periodic broadcast beacon frame (beacon). A node located in the overlapping area of two WPANs is called a bridge (bridge) and synchronizes the coordination of the two WPANs by forwarding heartbeat messages.

The THz-WPAN divides the network running time into a plurality of superframes (Superframes), and the PNC automatically adjusts the length of the superframes according to the size of the data volume. The superframe is mainly divided into a Beacon Period (BP), a Contention Access Period (CAP), and a Channel Time Allocation Period (CTAP), and a guard interval exists between the Beacon Period and the CAP. The BP period is used for PNC to broadcast beacon frames, and the frames contain the node information of the whole network, the time slot allocation condition and the start and stop time of the superframe period, so that the management allocation of the whole network is realized. The CAP period is used for each node to send a command frame, send a channel time slot request to the PNC, apply for a time slot for data to be sent, and in addition, the CAP period is also used for a new node to send an association request in the networking stage, and the node in the period adopts a CSMA/CA mechanism to access a channel. The CTAP time period accounts for 95% of the time length of the whole superframe, is the core time period of the whole network operation, is mainly used for data transmission among nodes, and consists of a plurality of CTAs, wherein the length of each CTA is fixed, and the starting time is contained in a beacon frame.

The network runtime of a terahertz wireless personal area network for communication across PANs (personal area networks) is composed of a coordinated superframe structure. The coordinated superframe structure includes 4 time periods in chronological order: the Beacon Alignment Period (BAP), the CAP Period and the 2 differently-acting CTAP periods are a Normal CTAP (N-CTAP) and a Public CTAP (P-CTAP), respectively. In the BAP period, the PNC in each WPAN respectively broadcasts beacon frames in the corresponding queue period, and the frames comprise the basic information of the nodes of the WPAN and the time and duration information of each period. The CAP time periods of 2 WPANs are the same, nodes with data transmission requirements respectively send time slot request frames to different PNCs in the CAP time period according to different WPANs, the PNCs can perform data transmission after successfully allocating time slots, in addition, during the coordinated synchronization of the two WPANs, the bridge nodes align beacon frames sent by the two PNCs through broadcasting heartbeat messages in the time period, and the mechanism of accessing channels in the time period is the same as that adopted in the CAP time period of a common superframe. The N-CTAP period and the P-CTAP period are divided into a plurality of CTAs with equal sizes, and are mainly allocated to the DEVs for data transmission, wherein the N-CTAP period mainly aims at data in the WPAN network, the P-CTAP period is used for data transmission of a link related to a bridge node, namely mainly aims at data between the WPAN networks, and a TDMA mechanism is adopted when the two periods access a channel. The P-CTAP period is again divided into two segments, with P-CTAP1 being primarily used for data transfer between nodes and bridge nodes within the WPAN1, and P-CTAP2 being primarily used for data transfer between the WPAN2 node and bridge nodes.

Terminals within communication range of the receiving node and outside the range of the transmitting node are hidden terminals. The hidden terminal may send a message to the same receiving node because it cannot hear that the sending node is sending, so that the message collides at the receiving node. After the conflict occurs, the sending node retransmits the conflict message, thereby reducing the utilization rate of the channel.

Aiming at the problems of time slot waste, unclear start time of coordinated superframes, high control overhead required by a superframe unified mechanism and the like caused by unbalanced traffic distribution in the existing cross-PAN data transmission mechanism, the prior art provides a high time slot utilization rate terahertz cross-PAN data transmission mechanism HTSU-PAN. The mechanism effectively improves the utilization rate of time slots and reduces the data transmission time delay by adopting three modes of implicit TDMA time slot allocation, beacon-free idle time period starting and bridge node superframe unification, thereby improving the network throughput.

In addition, the prior art also provides a data transmission mechanism of the MINN-PAN, and the specific idea of the mechanism is as follows:

1) data transmission between nodes in network and nodes between new networks

In the initial networking stage, when each in-network node sends a correlation request, each PNC extracts the SrcID, PNID and DestID information at the head of an MAC frame and records the information in an ID table item, when a newly-networked internetwork node and an in-network node need to perform data transmission, the PNCs of two PANs receive a time slot request, extract the SrcID, PNID and DestID and compare the time slot request with the recorded ID table one by one, when a certain table item is found to be consistent with the SrcID or DestID, the newly-networked internetwork node can know whether the in-network node belongs to PAN1 or PAN2, the PNC allocates a time slot for the newly-networked nodes, and the other PNC discards the time slot request frame because the table item is not found, and does not consider time slot allocation.

2) Data transmission between original internetwork node and new internetwork node

After monitoring beacon frames broadcast by two PNCs, each internetwork node respectively extracts corresponding information elements, mainly energy information elements, mainly comprising PNC capabilities and DEV capabilities. The PNC capabilities field value determines the priority of the PNC, the PNC with the higher value is regarded as the high-level PNC, then data transmission is needed between the newly-accessed network node and the original network node, when a channel time slot request is sent to the PNC, the high-level PNC only allocates time slots for the PNC, and the low-level PNC directly discards the message after receiving the message without any processing.

However, the prior art still does not solve the inter-PAN interference problem caused by the edge node, and in addition, after the node finds that the node is the edge node, how to report the information to the PNC of the PAN where the node is located efficiently and timely is also a problem to be solved urgently.

Disclosure of Invention

In view of the above, the present invention provides an adaptive edge node information reporting method for THz-WPAN, which introduces the concept of an edge node and enables a PNC to take measures in time slot allocation through a corresponding mechanism, so as to reduce or even eliminate inter-PAN interference caused by the edge node.

Based on the above purpose, the technical scheme provided by the invention is as follows:

a self-adaptive edge node information reporting method for a THz-WPAN is applied to a terahertz wireless network with a plurality of domain networks, wherein nodes in the terahertz wireless network are divided into a center node, an internetwork node and a conventional node, and the conventional node is divided into a common node and an edge node; the method comprises the following steps:

(1) before the non-central node is accessed to the network, the non-central node defaults to be a common node; when the node monitors a Beacon frame sent by a central node, preparing for network access operation, if a message sent by other network nodes different from the network identifier is monitored in the process and the Beacon frame sent by the center of other network is not monitored, the node judges the type of the node as an edge node, and the type information of the node is placed in an association request command frame and sent to the central node of the network;

(2) for a conventional node which is accessed to the network, in the network operation process, if the type of the node is changed, the type information is reported to a central node of the network after the type of the node is changed;

(3) the central node receives the type information reported by the conventional node, and replies to the type information after receiving the type information reported by the conventional node so as to confirm the reception of the type information reported by the node; if the central node and the node have message interaction, directly replying, otherwise, the central node carries reply information aiming at the node in the message interaction with other nodes and indirectly replys the node;

(4) and (3) after the conventional node in the step (2) sends the type information, receiving the reply information of the central node, and if the conventional node does not receive the direct reply of the central node in the channel time allocation period, performing general listening to process the received frame so as to receive the indirect reply of the central node.

Further, the specific way of placing the type information of the node in the association request Command frame and sending the type information of the node to the central node of the local network in the step (1) is to place the type information of the node in a value of a Command type field in the association request Command frame, wherein the Command type field is b15-b0, 0x 0000-0 x001E is used for representing the frame type, in the range, 0x 001D-0 x00FF are reserved value types, and a reserved value 0x001F is used for representing the association request frame carrying the type information of the node as an edge node; when the node type is a normal node, the sent association request frame type is 0x0000, and when the node type is an edge node, the sent association request frame type is 0x 001D.

Further, the specific way of reporting the type information to the central node of the local network in the step (2) is that the type information is sent to the central node through a time slot application frame in a contention access period, and the type information is carried to the central node through a data frame or an ACK immediate acknowledgement frame in a channel time allocation period.

Further, the specific way of sending the type information to the central node through the time slot application frame in the contention access period is as follows:

if the type of the conventional node is changed from the common node to the edge node, setting the value of the Command type field to 0x0020 when sending the time slot application frame;

if the type of the conventional node is changed from the edge node to the common node, setting the value of the Command type field to 0x0021 when sending the time slot application frame;

the type of the regular node is not changed, and the Command type field value in the slot application frame is set to 0x 0012.

Further, the specific way of carrying the type information to the central node through the data frame or the ACK immediate acknowledgement frame in the channel time allocation period is as follows:

if the number of the nodes in the network is not more than 127, reporting the type information of the nodes by using a single-value multicast address mode; specifically, if the node type is changed from a common node to an edge node, the node adds 127 to its own address value and places the added value in the DestID field of the data frame or the ACK frame; if the node type is changed from an edge node to a common node, the node adds 127 to the address value of the node and then places the node in the SrcID field of the data frame or the ACK frame; when the node type is not changed, the values in two fields of DestID and SrcID in a data frame or an ACK frame sent by the node are unchanged;

if the number of the nodes in the network is larger than 127, carrying the node type information by using a Frame type field in a Frame control field at the head of a data Frame or an ACK Frame; specifically, if the node type is changed from an edge node to a common node and the node is a data Frame sender, the node sets a Frame type field in a Frame header Frame control field of a data Frame to be sent to be 101; if the node type is changed from an edge node to a common node and the node is a data Frame receiver, the node sets a Frame type field in a Frame header Frame control field of an ACK Frame to be sent to be 111; if the node type is changed from a common node to an edge node and the node is a data Frame sending party, the node sets a Frame type field in a Frame header Frame control field of a data Frame to be sent to be 101 and sets a Reserved field in the Frame header Frame control field to be 1; if the node type is changed from a common node to an edge node and the node is a data Frame receiver, the node sets a Frame type field in a Frame header Frame control field of an ACK Frame to be sent to be 111 and sets Reserved in the Frame header Frame control field to be 1; when the node type is not changed, if the node type is a data Frame sending party, the Frame type field in the Frame header Frame control field of the data Frame to be sent by the node is set as a default Frame type value of 100, and if the node type is a data Frame receiving party, the Frame type field in the Frame header Frame control field of the ACK Frame to be sent by the node is set as a default Frame type value of 001.

Further, in step (3), if the central node receives the type information reported by the regular node in the channel time allocation period, the specific receiving manner is as follows:

the central node listens, receives a data frame or an ACK frame, judges whether the number of nodes in the network is greater than 127, and records the type information of the corresponding node according to the received frame if the number of the nodes in the network is not greater than 127 and the values of the DestID field and the SrcID field are not greater than 127; and if the number of the nodes in the network is more than 127, checking the value of the Frame type field of the received Frame, checking the value of the Reserved field in the Fragmentation control field as required, and recording the type information of the node corresponding to the Frame according to the values of the fields.

Further, the specific mode of the step (3) is as follows:

if the type information is reported to the central node by the conventional node through the data frame, the central node directly replies a normal ACK frame to indicate that the central node receives the type information reported by the conventional node;

if the central node does not perform message interaction with the conventional node reporting the type information, but performs message interaction with other nodes, in an ACK frame or a data frame interacted with other nodes, the ID of the conventional node reporting the type information to be replied is represented by combining a reserved bit, a reserved value and an existing value, so that the conventional node is replied.

Further, the specific way that the central node uses the reserved bit, the reserved value and the existing value to represent the ID of the regular node of the report type information to be replied is as follows:

if the central node uses the ACK frame to perform message interaction with other nodes, the ID of the conventional node of the report type information to be replied is represented as follows: b0 bits of the ID are represented by Reserved bits b23 of a Reserved field in a Fragmentation control field, b5-b 1 bits of the ID are represented by Reserved bits b15-b11 of the Reserved field in a Frame control field, b 7-b 6 bits of the ID are represented by values of a Frame type field, wherein when the value of the Frame type field is the existing value 001 or Reserved values 101, 110 and 111, the bits b 7-b 6 bits representing the ID are 00, 01, 10 or 11 respectively;

if the central node uses the data frame to perform message interaction with other nodes, the ID of the conventional node of the report type information to be replied is represented as follows: b0 bits of the ID are represented by Reserved bits b23 of a Reserved field in a Fragmentation control field, b5 to b1 bits of the ID are represented by Reserved bits b15 to b11 of the Reserved field in a Frame type field, b7 to b6 bits of the ID are represented by a value of a Frame type field and a value of a Protocol version field in the Frame control, wherein when the value of the Protocol version field is an existing value 000 or Reserved values 001, 010 and 011, the bits b7 to b6 bits representing the ID are 00, 01, 10 or 11, respectively, and when the value of the Frame type field is an existing value 010, the bits b7 to b6 bits of the ID are also 00;

if the Reserved bit of the Reserved field is not used, it indicates that the corresponding bit in the ID is 0.

Further, the specific mode of the step (4) is as follows:

(401) checking a target node identifier in a received frame, if the target node identifier is the address of the target node identifier, directly receiving, otherwise checking a source node identifier in the frame, if the source node identifier is not 0, directly discarding, and if the source node identifier is 0, indicating that a source address of the frame is a central node, and receiving the central node;

(402) for the received frame, checking the value of the frame type field, and respectively operating as follows according to the frame type value:

a) the frame type value is 001, that is, the frame is an ACK frame;

at this time, looking up the values of Reserved fields in the Fragmentation control and the Frame control, if both are 0, determining that the Frame is a common ACK Frame without carrying center reply information, and not performing subsequent operation; if the values of the Reserved fields are not all 0, forming a device ID by using the existing value of the Frame type field and the values of the b5-b 0 bit corresponding fields, then comparing the device ID with the self ID, and if the values are equal, indicating that the central node has received the type information reported by the node, and ending the general listening; if not, continuing to monitor;

b) the frame type value is 101, 110 or 111, namely the frame is an ACK frame carrying the reply information;

at the moment, a device ID is formed by the value of a Frame type field and the value of a field corresponding to b5-b 0 bits, then the device ID is compared with the ID of the device, if the device ID is equal to the ID of the device ID, the central node receives the type information reported by the node, and the general listening is finished; if not, continuing to monitor;

c) the frame type value is 010, that is, the frame is a data frame;

at this time, looking up the values of Reserved fields in the Protocol version field, the Fragmentation control field and the Frame control field, if all the values are 0, determining that the Frame is a common data Frame which does not carry the center reply information, and not performing subsequent operation; if the values of the fields are not all 0, forming a device ID by using the existing value of the Protocol version field, the values of b 7-b 6 bit corresponding fields and the values of b5-b 0 bit corresponding fields, then comparing the device ID with the self ID, and if the device ID is equal to the self ID, indicating that the center has received the type information reported by the node, and ending the general listening; if not, continuing to monitor.

As can be seen from the above description, the technical scheme of the invention has the beneficial effects that:

1. the invention further subdivides the node types, introduces the concept of the edge node in the multi-PAN terahertz wireless personal area network, provides the inter-PAN interference problem caused by the edge node, finds out the reason of the interference problem suffered in the N-CTAP time period, and provides a solution for solving the interference problem.

2. The invention makes PNC find a DEV as an edge node through a corresponding mechanism, and can take measures on time slot allocation, thereby reducing or even eliminating inter-PAN interference brought by the edge node.

3. The method can efficiently and timely transmit the node type change information to the PNC in the PAN without increasing additional control overhead.

Drawings

To more clearly describe this patent, one or more drawings are provided below to assist in explaining the background, technical principles and/or certain embodiments of this patent.

FIG. 1 is a schematic diagram of the structure of a THz-WPAN.

FIG. 2 is a schematic diagram of a superframe structure of THz-WPAN.

FIG. 3 is a schematic diagram of node types in a THz-WPAN network.

Fig. 4 is a schematic diagram of a hidden terminal problem.

FIG. 5 is a diagram of a generic frame structure for a THz-WPAN.

FIG. 6 is a schematic diagram of a command frame structure of the THz-WPAN.

FIG. 7 is a diagram of a data frame structure of the THz-WPAN.

FIG. 8 is a diagram of an ACK frame structure for a THz-WPAN.

Fig. 9 is a schematic diagram of an association request command frame body structure.

Fig. 10 is a schematic diagram of a slot application frame body structure.

Fig. 11 is a diagram illustrating a structure of a Frame control field.

FIG. 12 is a diagram showing a structure of a Fragmentation control field.

Fig. 13 is a flowchart of determining an edge node before network entry.

Fig. 14 is a flowchart of the slot request frame reporting its own type.

Fig. 15 is a flowchart of the CTAP period node report type information when the number of nodes is greater than 127.

Fig. 16 is a flowchart of the center node receiving type information when the number of nodes is greater than 127.

Fig. 17 is a flowchart of the CTAP period node report type information when the number of nodes is not more than 127.

Fig. 18 is a flow chart of the operation of a node that does not report type information.

Fig. 19 is a flowchart of the center node reception type information in the CTAP period when the number of nodes is not more than 127.

Fig. 20 is a flow chart of the central node sending back a reply message.

Fig. 21 is a flow chart of a node receiving a reply message.

Detailed Description

In order to facilitate understanding of the technical solutions of the present patent by those skilled in the art, and to make the technical objects, technical solutions and advantages of the present patent more apparent and fully support the scope of the claims, the technical solutions of the present patent are described in detail in the following embodiments.

Fig. 1 is a schematic structural diagram of a THz-WPAN terahertz wireless personal area network, which includes a central control node PNC and a plurality of nodes DEV, where the PNC periodically broadcasts beacon frames beacon to provide basic networking information, and data are also transmitted between the DEVs and the PNC.

The THz-WPAN divides the network running time into an infinite number of superframes (Superframes), and the PNC can automatically adjust the Superframe length according to the data size. As shown in fig. 2, each superframe mainly includes a Beacon Period (BP), a Contention Access Period (CAP), and a Channel Time Allocation Period (CTAP), and a guard interval exists between the Beacon Period and the CAP.

As shown in fig. 3, when a terahertz wireless personal area network communicates across the personal area networks, for each wireless personal area network WPAN, a node a with a higher priority competes for becoming a PNC of the network, and a node a located in an overlapping area of two WPANs is called a bridge (bridge), and mainly functions to coordinate and synchronize the two WPANs by forwarding heartbeat messages.

If a terminal is within communication range of the receiving node but outside the range of the transmitting node, the problem of hidden terminals arises. As shown in fig. 4, when node a sends a packet to node B, node C is out of the communication range of node a (sending node) and in the communication range of node B (receiving node), and therefore node C is a hidden terminal. The hidden terminal can be divided into a hidden transmitting terminal and a hidden receiving terminal. When the node A sends a message to the node B, the node C thinks that the node C can send the message because the node C can not perceive the sending of the node A. If node C sends a packet to node B or node D at this time, a collision occurs at node B, and node C becomes a hidden sending terminal. One solution to prevent C from sending messages is to use a handshake mechanism. Such as: before sending data message To B, node A sends RTS (request To Send) control message; after receiving the RTS sent by a, B responds To a CTS (clear To send) control message, and a starts sending a data message To B after receiving the CTS (if a does not receive the CTS message, a considers that a collision occurs at B, and retransmits the RTS control message). Therefore, the hidden terminal C can hear the CTS message sent by the B, know that the A is ready to send the data message to the B, and delay the sending of the C, thereby avoiding the problem of hiding the sending terminal. But this handshake mechanism does not completely solve the hidden sending terminal problem.

Still referring to fig. 4, after C receives the CTS message of B, the transmission is delayed, and at this time, if node D transmits RTS to C, D cannot receive the CTS of C because C cannot transmit information at this time. Then D considers that collision has occurred and retransmits RTS, which is a hidden receiving terminal problem. It is clear that during the communication between a and B D is not able to receive the response message CTS of C, which causes unnecessary retransmissions.

In view of this, the present embodiment proposes an adaptive edge node information reporting method for THz-WPAN, which assumes that wireless communication between nodes in a plurality of terahertz wireless personal area networks is omni-directional communication, PNCs between the personal area networks cannot directly communicate, initially all nodes are not edge node types by default, and all nodes in the network know node number information of the network.

The method uses a plurality of frame structures in operation, including the following:

(1) universal frame

As shown in fig. 5, the generic frame structure includes two parts, a frame header and a frame body, and the frame body includes two parts, a frame payload and an FCS check.

(2) Command frame

As shown in fig. 6, the command frame includes two parts, a frame header and a frame body, and the frame body includes a command type, a length and a command payload 3 part, and does not include an FCS check part.

(3) Data frame

As shown in fig. 7, the data frame includes two parts, a frame header and a frame body, and the frame body includes two parts, a data payload and an FCS check.

(4) ACK frame

As shown in fig. 8, the ACK frame includes only a frame header MAC header.

In the N-CTAP period in the coordinated superframe, the nodes in the coordinated network transmit and receive data frames simultaneously, but part of conventional nodes in the two networks are exposed in the communication range of the conventional nodes in the other network, so that the nodes are interfered by the data transmitted by the conventional nodes in the other network during normal data receiving. In order to better reduce the interference suffered by the nodes in the network in the N-CTAP period, the conventional node types in the network are subdivided into common nodes and edge nodes according to whether the adjacent network node messages are sensed or not on the basis of the original nodes in the network. Therefore, the method expands the node types in the multi-PAN terahertz wireless personal area network from 3 existing types (PNC, internetwork node and common node) to 4 types (PNC, internetwork node, common node and edge node). The method comprises the following specific steps:

(1) a central node: i.e., PNC nodes, such as nodes PNC1 and PNC2 in fig. 3, there is only one PNC node per personal area network (i.e., PAN), and the PNC nodes of different PANs cannot communicate directly.

(2) An internetwork node: a node capable of communicating with the PNC nodes of both PANs, such as node A in FIG. 3; the type node transmits data in the P-CTAP period.

(3) And (3) common nodes: nodes which can only communicate with the nodes of the PAN in which the nodes are positioned, such as node 1 and node a in figure 3, but are not PNC and internetwork nodes; the type node transmits data in the N-CTAP period;

(4) edge nodes: regular nodes capable of direct communication with regular nodes of other PANs, such as node 2 and node d in fig. 3; the type node transmits data in the N-CTAP period, but may be interfered by DEV nodes of other PANs while transmitting and receiving information.

A node can autonomously determine whether it is an edge node: first, it is not a PNC; secondly, the self does not receive the information of PNC of other PAN; then, a message of a regular node of the other PAN is received, and thus, it can be determined that it is an edge node.

Based on a new node classification mode, the method realizes a reporting mechanism of edge node information by adopting the following modes:

before a node is accessed to a network

Before entering the network, the non-PNC node defaults to be a common node. When the node detects a Beacon frame sent by a nearby network PNC, the node prepares to carry out network access operation, if a message sent by other network nodes different from the network PNID is detected in the process and the Beacon frame sent by the PNC of other networks is not detected, namely the Beacon frame is not an internetwork node type, the node type is determined as an edge node type, and the information is put in an association request command frame and sent to the PNC. The association request command frame is a command frame whose frame body structure is shown in fig. 9.

The Specific method is that the node information is placed in the value of the Command type field in the association request Command frame, the Command type field is b15-b0, wherein 0x 0000-0 x001E is used for representing various frame types, 0x 001D-0 x00FF is a reserved value type, 0x 0100-0 xFFFF is used for Vendor Specific, and the reserved value 0x001F is used for representing a new frame type: namely, the association request frame carrying the self node type information as the edge node. When the node type is a normal node, the type of the association request frame sent by the node is 0x0000, and if the node type is an edge node, 0x001D is used to indicate the type of the time slot request frame sent by the node. If the DEV receives the association request reply frame, confirming that the PNC has received the node type information of the node; and then no longer reports itself as an edge node. If it cannot be confirmed whether the PNC has received the reported information, the chance report continues at a subsequent time.

After the node is accessed to the network

If the node type of the node that has already been networked changes due to the change of the network topology during the operation of the network, the reporting mechanism of the node type change information is as follows.

(1) DEV reporting type change to PNC

In the network operation process, if the type of the regular node changes, after the type of the regular node changes (for example, the regular node changes into the edge node, or the edge node changes into the regular node), the PNC needs to be informed of the status information report.

1) In the CAP period, if the node needing to be reported needs to send a time slot application frame, the information of the type conversion of the node is informed to the PNC through the time slot application frame. The slot application frame is a command frame, and the frame body structure thereof is shown in fig. 10:

the specific implementation process is as follows:

a) if the type of the regular node is not changed, a default frame type is filled in when the slot application frame is sent, namely the value of the Command type field is 0x0012, which indicates that the node is the regular node.

b) If the type of the regular node is changed from the normal node to the edge node, a new frame type is used when the slot application frame is transmitted, i.e. the Command type field value is 0x 0020. Indicating that the node has changed from a normal node to an edge node.

c) If the type of the regular node is changed from the edge node to the normal node, a new frame type is used when the slot application frame is transmitted, i.e., the Command type field value is 0x 0021. Indicating that the node has changed from an edge node to a normal node.

d) The regular node confirms that the PNC has received the information reported by itself if it receives the slot request reply message of the PNC.

e) If it cannot be confirmed whether the PNC has received the reported information, the chance report continues at a subsequent time.

2) In the CTAP period, if a node needs to report a type change to the PNC and the node needs to perform data interaction with other nodes, the node type change information may be carried to the PNC using a data frame or an immediate acknowledgement frame (ACK frame), specifically as follows:

a) if the number of nodes in the network is not more than 127, the nodes use a single-value multicast address (only 1 address value, but report information to two nodes, namely a destination node and a PNC) mode when reporting the self node type information.

If the node type is not changed, the values in two fields of DestID and SrcID in a data frame or an ACK frame sent by the node are unchanged; if the node type changes, it places the address value of the node plus 127 in the DestID or SrcID field of the data frame or ACK frame: if the node type is changed from a common node to an edge node, adding 127 to the address value of the node to be changed into the destID field of the data frame or the ACK frame; if the node type is changed from the edge node to the common node, the address value of the node is added with 127 and is placed in the SrcID field of the data frame or the ACK frame.

In order to receive the type information reported by the node in the CTAP period, the PNC needs to perform flood listening, namely the PNC firstly checks the DestID field after receiving the data frame or the ACK frame, and does not discard the DestID field if the PNC does not receive the self address; then judging whether the total number of the nodes in the PAN is not more than 127; if yes, judging whether the DestID or the SrcID is larger than 127; if yes, the source node of the frame is recorded as the corresponding type.

b) If the number of nodes in the network is greater than 127, the Frame type field in the Frame control field of the header of the data Frame or the ACK Frame is used to carry the node type information, and fig. 11 shows the structure of the Frame control field in the MAC header.

If the type of the node is not changed, when the node interacts with other nodes, if the node is a sender, setting a Frame type field (b 5-b3 bits in fig. 11) in a Frame control field of a Frame header of a data Frame to be sent as a default Frame type value of 100; if the node is a receiver, setting a Frame type field in a Frame control field of a Frame header of an ACK Frame to be sent as a default Frame type value of '001'.

If the node type is changed and the original edge node type is changed into the common node type, judging at this time, if the node is a data Frame sender, setting a Frame type field (b 5-b3 bits in figure 11) in a Frame control field of a header of a data Frame to be sent to be '101', and indicating that the node type information carried by the node is the data Frame type changed from the edge node type into the common node type; if the node is a data Frame receiver, namely an ACK Frame sender, setting a Frame type field in a Frame control field of a header of an ACK Frame to be sent to be '111', and indicating that the node type information carried by the node is a data Frame type converted from an edge node type to a common node type.

If the node type is changed and the original common node type is changed into the edge node type, then judging, if the node is a sender, setting a Frame type field in a Frame control field of a header of a data Frame to be sent to be 101, and setting a Reserved field in the Frame control field to be 1 (b 23 bit in figure 12), wherein the Frame type information carrying the node type is the data Frame type converted from the common node type into the edge node type; if the node is a receiving party, setting a Frame type field in a Frame control field of an ACK Frame header to be sent to be '111' and setting a Reserved field in the Frame control field to be 1, wherein the Reserved field indicates that the node carrying the node type information is a data Frame type converted from a common node type to an edge node type.

At this time, the PNC needs to perform extensive listening to receive information, that is, after receiving a data Frame or an ACK Frame, the PNC first checks the DestID field, if the address of the PNC is not discarded, then checks the value of the Frame type field of the Frame, and checks the value of the Reserved field in the Fragmentation control field as required; if the values of the fields have the condition, the node type information corresponding to the frame is recorded.

(2) PNC reply to DEV

After receiving the type change information reported by the conventional node, the PNC replies the conventional node and confirms that the information reported by the node is received; the specific mode is as follows:

1) if the node reporting the information sends the data frame to the PNC, the PNC directly performs implicit reply in the ACK frame corresponding to the data frame (the content of the ACK frame is not different from the normal content), and informs the node that the node type change information is received.

2) If the PNC does not perform message interaction with the node reporting the information but performs message interaction with other nodes, the ID of the reporting node to be replied to is represented in an ACK frame or a data frame by combining a reserved bit, a reserved value and an existing value (8 bits are needed to represent DEVID, respectively b 7-b 0), and the reporting node is replied by using the ACK frame or the data frame, which is specifically as follows:

a) PNC replies with ACK frame

If the PNC replies by using the ACK frame, the PNC expresses the DEVID of the node to which the PNC replies by using a reserved bit, a reserved value and an existing value in a combined mode; specifically, b0 of DEVID is represented by Reserved bit b23 of Reserved field in Fragmentation control field; b5-b 1, represented by Reserved bits b15-b11 of Reserved field in Frame control field; b 7-b 6 are represented by using the existing value 001 (for type ACK Frame) and reserved values 101, 110, 111 (for type ACK Frame) of the Frame type field, and the corresponding relationship between these values and the bit values of b 7-b 6 is as follows: 001-00, 101-01, 110-10, 111-11. When the reserved bits are not used, the values are all 0.

b) PNC replies using data frames

If replying with a data frame, the PNC represents the DEVID of the node to which the PNC replies by combining the reserved bit with the existing value; specifically, b0 of DEVID is represented by Reserved bit b23 of Reserved field in Fragmentation control field; b5-b 1, represented by Reserved bits b15-b11 of Reserved field in Frame type field; b 7-b 6 use the existing value 010 (indicating the type is data Frame) of the Frame type field to indicate that the bit values of b 7-b 6 are 00, and use the existing value 000 and reserved values 001, 010, 011 of the Protocol version field (always 000) in the Frame control to indicate that the bit values of b 7-b 6 are 00, 01, 10, 11, respectively.

(3) DEV receiving PNC reply

In the CTAP period, the node that has sent the self-type message to the PNC and has not received the PNC reply message overhears, which specifically operates as follows:

if the frame is received, firstly checking the DestID in the frame; if the DestID is the self address, directly receiving; otherwise, checking the SrcID in the frame, and directly discarding if the SrcID is not 0; if the value is 0, the source address of the frame is PNC; and then checking the value of the frame type field, and respectively operating as follows according to the frame type value:

1) the frame type value is "001"

Indicating that the frame is an ACK frame; checking the values of reserved fields in the Fragmentation control and the Frame control, if the values are both 0, determining that the Frame is a common ACK Frame which does not carry PNC reply information, and not performing subsequent operation; if the values of the reserved fields are not all 0, forming a DEVID by using the existing value (001, representing that the bit values of b 7-b 6 are 00) of the Frame type field and the value (representing the bit values of b5-b 0) of the 6-bit reserved field, then comparing the DEVID with the self ID, and if the DEVID is equal to the self ID, representing that the PNC has received the type information reported by the node, ending the flood listening; if not, continuing to monitor.

2) The frame type value is one of "101", "110" and "111

Indicating that the frame is an ACK frame carrying the reply information; forming a DEVID by using the value of a Frame type field (one of 3 reserved values and representing the values of b 7-b 6 bits) and the value of the 6-bit reserved field (representing the values of b5-b 0 bits), comparing the DEVID with the self ID, and if the DEVID and the self ID are equal, indicating that the PNC has received the type information reported by the node, and ending the flood listening; if not, continuing to monitor.

3) The frame type value is "010"

Indicating that the frame is a data frame; checking the values of reserved fields in the Protocol version field, the Fragmentation control field and the Frame control field, if the values are all 0, determining that the Frame is a common data Frame which does not carry PNC reply information, and not performing subsequent operation; if the values of the fields are not all 0, forming DEVID by using the existing value (000) and reserved values (001, 010 and 011) (representing the values of b 7-b 6 bits) of the Protocol version field and the value of the 6-bit reserved field (representing the values of b5-b 0 bits), then comparing the DEVID with the self ID, and if the DEVID is equal to the self ID, indicating that the PNC has received the type information reported by the node, and ending the overhearing; if not, continuing to monitor.

The following are more specific examples:

after the node device DEV is powered on, the node starts to monitor whether a network exists nearby for network access, the monitoring duration is about one superframe length, if the node type is determined to be an edge node type by an edge node type determination method in the monitoring process, and the type information is placed in an association request frame for network access operation.

As shown in fig. 13, the specific operation is:

step 1: the DEV monitors a Beacon frame of a network PNC to prepare for network access;

step 2: if the DEV listens to non-PNC information from other networks in the process, executing the step 3; otherwise, executing step 4;

and step 3: the DEV node type is an edge node, a Command type field in an association request Command frame to be sent uses a reserved value of 0x001F, and step 5 is executed;

and 4, step 4: the DEV node type is an edge node, a Command type field in an association request Command frame to be sent uses an original value of 0x0000, and a step 5 is executed;

and 5: an association request command frame is sent to the PNC.

After network access, if a node which has already accessed the network is in the network operation process, node type conversion occurs due to network change, and a reporting mechanism of the node type is as follows:

(1) in the network operation process, if the interaction between the conventional node and the PNC exists, the state information is informed to the PNC through a channel time request command frame.

As shown in fig. 14, the specific operation steps are:

step 1: if the type of the DEV is not changed, filling a default frame type when a time slot application frame is to be sent, namely the field value of the Command type is 0x 0012; executing the step 4;

step 2: if the DEV type is changed from a common node to an edge node, filling a new frame type in a time slot application frame to be sent, wherein the field value of the Command type is 0x 0020; executing the step 4;

and step 3: if the type of the DEV is changed from the edge node type to the conventional node type, filling a new frame type in a time slot application frame to be sent, namely the field value of the Command type is 0x 0021; executing the step 4;

and 4, step 4: the DEV sends a slot request frame to the PNC.

(2) If the conventional node has accessed the network and has no time slot application in the CAP period of the superframe, if the node needs to perform data interaction with other nodes, the node type information can be carried to the PNC by using an immediate acknowledgement frame or a data frame.

And if the number of the nodes in the network is more than 127, carrying the node type information by using a Frame type field in a Frame control in a data Frame or an ACK Frame.

As shown in fig. 15, the specific operation steps of the node DEV are as follows:

step 1: using the data frame to carry the node type information to execute the step 2, and using the ACK frame to carry the node type information to execute the step 5;

step 2: if the node type of the DEV is not changed, the DEV uses a default Frame type value of 100 in a Frame type field in a Frame control field in a header of a data Frame to be transmitted; executing the step 8;

and step 3: if the type of the DEV node is changed from a common node type to an edge node type, the DEV uses a reserved Frame type in a Frame type field in a Frame control field in a header of a transmitted data Frame, and the type value of the DEV is '101'; executing the step 8;

and 4, step 4: if the type of the DEV node is changed from the edge node type to the common node type, the DEV uses a reserved Frame type in a Frame type field in a Frame control field in a header of a transmitted data Frame, and the type value of the DEV is '110'; executing the step 8;

and 5: if the node type of the DEV is not changed, the DEV uses a default Frame type value of '001' in a Frame type field in a Frame control field in a header of an ACK Frame to be transmitted; executing the step 8;

step 6: if the DEV node type is changed from a common node type to an edge node type, the DEV uses a reserved Frame type in a Frame type field in a Frame control field in a header of a sent ACK Frame, and the type value of the DEV is '111'; the Reserved position in the Fragmentation control field is "0"; executing the step 8;

and 7: if the DEV node type is changed from a common node type to an edge node type, the DEV uses a reserved Frame type in a Frame type field in a Frame control field in a header of a sent ACK Frame, and the type value of the DEV is '111'; the Reserved position in the Fragmentation control field is "1"; executing the step 8;

and 8: the DEV sends a data frame or an ACK frame;

accordingly, as shown in fig. 16, the specific operation steps of the PNC are:

step 1: the PNC monitors in the network and executes the step 2;

step 2: looking up the DestID field of the sensed frame, if not the self ID, executing step 3; otherwise, executing step 4;

and step 3: looking up the frame types, and if the frame types are '001, 100, 101, 110 and 111', executing a step 4; otherwise, executing step 9;

and 4, step 4: receiving the frame to obtain frame type information, and if the frame type information is '001, 100, 101 and 110', executing the step 5; if the value is '111', executing the step 6; otherwise, executing step 9;

and 5: the PNC marks the node type through the corresponding frame type information; executing the step 9;

step 6: the PNC checks a Reserved field in the Fragmentation control field, if the field is 1, the step 7 is executed, otherwise, the step 8 is executed;

and 7: the PNC marks the node type as a common node from the edge node; executing the step 9;

and 8: the PNC marks the node type as an edge node from a common node; executing the step 9;

and step 9: the mechanism is ended.

If the number of nodes in the network is not greater than 127, the DEV uses the multicast address method when reporting the self node type information.

As shown in fig. 17, the specific operation steps of the DEV are:

step 1: if the node type is changed, executing step 2; otherwise, executing step 5;

step 2: DEV adds 127 to the ID value of the destination address of the data frame or ACK frame to be sent, and places the data frame or ACK frame in the DestID field; executing the step 3;

and step 3: if the node type is changed from the common node to the edge node, executing the step 4; otherwise, executing step 5;

and 4, step 4: in the data frame (or ACK frame) to be sent, adding 127 to the ID value of the self node in the SrcID field of the frame, and executing the step 5;

and 5: the DEV transmits a data frame (or ACK frame) to end the operation.

At this time, the operation flow of other DEVs in the network is shown in fig. 18, and the specific steps are as follows:

step 1: the DEV listens in the network, and if the DEV listens the frame, the step 2 is executed;

step 2: checking the DestID in the frame, if the DestID is larger than 127, executing the step 3, otherwise, executing the step 4;

and step 3: subtract 127 from the DestID value and perform step 4;

and 4, step 4: comparing with the own DEVID value, if the DEVID value is equal, executing the step 5, otherwise, executing the step 6;

and 5: receiving the frame, and executing the step 7;

step 6: discarding the frame, and executing step 7;

and 7: finishing the operation;

at this time, the operation flow of the PNC is shown in fig. 19, and the specific steps are as follows:

step 1: the PNC monitors in the network and executes the step 2;

step 2: checking the DestID of the intercepted frame, if the DestID is larger than 127, executing the step 3, otherwise, executing the step 7;

and step 3: checking the SrcID field in the frame, and if the SrcID field is larger than 127, executing a step 4; otherwise, executing step 5;

and 4, step 4: subtracting 127 from the SrcID value in the frame to obtain the ID value of the source DEV, and executing the step 6;

and 5: the PNC marks the source DEV type as a common node type, and step 7 is executed;

step 6: the PNC marks the source DEV type as an edge node type, and step 7 is executed;

and 7: the PNC ends the operation.

The PNC replies to the DEV after receiving the node type information of the DEV and confirms whether the node type information of the DEV is received or not. As shown in fig. 20, the specific steps are:

step 1: if the PNC exists in the information interaction of the DEV, executing the step 2, otherwise executing the step 4;

step 2: if the PNC replies the data frame of the DEV, executing the step 3, otherwise executing the step 4;

and step 3: the PNC sends an ACK frame to confirm the node type information of the DEV; executing the step 5;

and 4, step 4: and the DEVID of the DEV to be replied is carried in the ACK message replied to other nodes by the PNC for replying, and the step 5 is executed.

And 5: the PNC ends the operation.

Accordingly, the flow of the node DEV receiving the reply message is as shown in fig. 21, and the specific operations are as follows:

step 1: the DEV listens in the network and executes the step 2;

step 2: the DEV firstly checks a DestID field in a message frame, if the DestID field is the address of the self node, the step 3 is executed, and if the DestID field is not the address of the self node, the step 4 is executed;

and step 3: checking the SrcID field and the frame type field of the frame, if the SrcID is 0 and the frame type field is 001, executing the step 8, otherwise, executing the step 1;

and 4, step 4: checking the SrcID of the frame, if the SrcID of the frame is 0, executing a step 5, and otherwise, executing a step 7;

and 5: looking up the frame type field, if the field is '001, 101, 110, 111', executing the step 6, otherwise executing the step 7;

step 6: looking up the DEVID, if the DEVID is the same as the self ID, executing a step 8, otherwise, discarding the frame and executing a step 1;

and 7: discarding the frame and executing the step 1;

and 8: the listening is ended and the DEV ends the operation.

In a word, the concept of the edge node is introduced into the communication of the cross-terahertz wireless personal area network, so that the reason of the interference problem suffered by the N-CTAP time period can be found out, and a solution idea is provided for solving the interference. Meanwhile, the invention provides a self-adaptive edge node information reporting method. When the node finds that the node is the edge node, the node can report the node type information to the PNC of the personal area network where the node is located efficiently and timely under the condition that extra control overhead is not increased. Thus, if the PNC finds a DEV to be an edge node, measures can be taken on the slot allocation to reduce or even eliminate inter-PAN interference caused by the edge node.

It should be understood that the above description of specific embodiments of this patent is merely exemplary of the disclosure set forth to facilitate understanding of the patent disclosure by those skilled in the art, and is not intended to limit the scope of the patent to these examples. Those skilled in the art can fully appreciate the technical solutions of the present patent application without any creative effort by combining technical features, replacing some technical features, adding more technical features, and the like for each of the embodiments listed in the present patent application. All such embodiments are within the scope of the patent claims.

Claims

1. A self-adaptive edge node information reporting method for a THz-WPAN is characterized by being applied to a terahertz wireless network with a plurality of domain networks, wherein nodes in the terahertz wireless network are divided into a center node, an internetwork node and a conventional node, and the conventional node is divided into a common node and an edge node; the method comprises the following steps:

2. The adaptive edge node information reporting method for the THz-WPAN according to claim 1, wherein the type information of the node is placed in the association request Command frame and sent to the central node of the local network in step (1) in such a way that the type information of the node is placed in a value of a Command type field in the association request Command frame, the Command type field is b15-b0, wherein 0x 0000-0 x001E is used for representation of a frame type, in this range, 0x 001D-0 x00FF is a reserved value type, and a reserved value 0x001F is used for representing the association request frame carrying the type information of the node as the edge node; when the node type is a normal node, the sent association request frame type is 0x0000, and when the node type is an edge node, the sent association request frame type is 0x 001D.

3. The adaptive edge node information reporting method for the THz-WPAN according to claim 2, wherein the type information is reported to the central node of the local network in step (2) in such a manner that the type information is transmitted to the central node through a slot application frame in a contention access period and is carried to the central node through a data frame or an ACK immediate acknowledgement frame in a channel time allocation period.

4. The adaptive edge node information reporting method for the THz-WPAN as claimed in claim 3, wherein the specific way of sending the type information to the central node through the slot application frame in the contention access period is as follows:

5. The adaptive edge node information reporting method for THz-WPAN as claimed in claim 3, wherein the specific way of carrying the type information to the central node through the data frame or the ACK immediate acknowledgement frame in the channel time allocation period is:

6. The adaptive edge node information reporting method for the THz-WPAN as claimed in claim 5, wherein in the step (3), if the center node receives the type information reported by the regular node during the channel time allocation period, the specific receiving manner is:

7. The adaptive edge node information reporting method for THz-WPAN as claimed in claim 3, wherein the step (3) is embodied by:

8. The adaptive edge node information reporting method for THz-WPAN as claimed in claim 7, wherein the central node indicates IDs of regular nodes to which report type information is replied by using reserved bits, reserved values and existing values in a combined manner by:

9. The adaptive edge node information reporting method for THz-WPAN as claimed in claim 8, wherein step (4) is embodied by:

a) the frame type value is 001, that is, the frame is an ACK frame;

c) the frame type value is 010, that is, the frame is a data frame;